Comprehensive Notes on Age-Related Changes in Human Skin
Skin Changes Across the Lifespan: From Newborn to Senescence
Skin Development from Birth
- Newborn Skin: Initially thin and delicate.
- Subcutaneous Fat Deposition: Occurs after birth, crucial for:
- Thermoregulation
- Protection
- Energy Reserve
General Trends in Skin Aging
- Skin Thickening: Generally thickens with age due to dermal changes and damaged proteins.
- Noticeable Aging: Typically begins around age 50.
1. Breakdown of Collagen
- Role: Provides structural support, strength, and elasticity.
- Aging Process: Decreased production, fragmentation, and disorganization, accelerated by UV.
- Impact: Loss of elasticity/firmness, wrinkles/fine lines, reduced tensile strength.
2. Decrease in Subcutaneous Fat
- Role: Contributes plumpness, insulation, cushioning.
- Aging Process: General reduction in volume.
- Impact: Loss of facial volume, increased skin laxity, greater susceptibility to cold, prominence of vessels/bones.
3. Decrease in Sebum Production
- Role: Hydrates, lubricates, protects, provides antimicrobial properties.
- Aging Process: Significant reduction, especially post-menopause.
- Impact: Dry skin (xerosis), impaired barrier function, increased itchiness.
4. Decrease in Melanin
- Role: UV protection, determines skin tone.
- Aging Process: Fewer active melanocytes, less uniform distribution; localized increase in sun-exposed areas (age spots).
- Impact: Paleness, increased susceptibility to sunburn/UV damage, uneven pigmentation.
5. Decrease in Hair Replacement
- Cycle: Old hairs shed and replaced by new.
- Aging Process: Follicles become less efficient, growth phase shortens, resting phase lengthens; follicles miniaturize.
- Impact: Thinner hair
